bindings: Add empty checks for toV8()

Source/bindings/core/v8/ScriptController.cpp

 /*
  * Copyright (C) 2008, 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 335 matching lines @@
 
 static NPObject* createScriptObject(LocalFrame* frame, v8::Isolate* isolate)
 {
     ScriptState* scriptState = ScriptState::forMainWorld(frame);
     if (!scriptState->contextIsValid())
         return createNoScriptObject();
 
     ScriptState::Scope scope(scriptState);
     LocalDOMWindow* window = frame->localDOMWindow();
     v8::Local<v8::Value> global = toV8(window, scriptState->context()->Global(), scriptState->isolate());
+    if (global.IsEmpty())
+        return createNoScriptObject();
     ASSERT(global->IsObject());
     return npCreateV8ScriptObject(isolate, 0, v8::Local<v8::Object>::Cast(global), window);
 }
 
 NPObject* ScriptController::windowScriptNPObject()
 {
     if (m_windowScriptNPObject)
         return m_windowScriptNPObject;
 
     if (canExecuteScripts(NotAboutToExecuteScript)) {
@@ skipping 16 matching lines @@
     if (!canExecuteScripts(NotAboutToExecuteScript))
         return createNoScriptObject();
 
     ScriptState* scriptState = ScriptState::forMainWorld(frame());
     if (!scriptState->contextIsValid())
         return createNoScriptObject();
 
     ScriptState::Scope scope(scriptState);
     LocalDOMWindow* window = frame()->localDOMWindow();
     v8::Local<v8::Value> v8plugin = toV8(plugin, scriptState->context()->Global(), scriptState->isolate());
-    if (!v8plugin->IsObject())
+    if (v8plugin.IsEmpty() || !v8plugin->IsObject())
         return createNoScriptObject();
 
     return npCreateV8ScriptObject(scriptState->isolate(), 0, v8::Local<v8::Object>::Cast(v8plugin), window);
 }
 
 void ScriptController::clearWindowProxy()
 {
     // V8 binding expects ScriptController::clearWindowProxy only be called
     // when a frame is loading a new page. This creates a new context for the new page.
 
@@ skipping 187 matching lines @@
         for (size_t i = 0; i < resultArray->Length(); ++i) {
             v8::Local<v8::Value> value;
             if (!resultArray->Get(scriptState->context(), i).ToLocal(&value))
                 return;
             results->append(value);
         }
     }
 }
 
 } // namespace blink